Transtensional opening of Cenozoic deep basins at the northeastern edge of Antarctica induced by intracontinental accommodation of oceanic transform shear.

• Main Authors: STORTI, Fabrizio, ROSSETTI, FEDERICO, SALVINI, Francesco
• Other Authors: Storti, Fabrizio, Rossetti, Federico, Salvini, Francesco
• Format: Other/Unknown Material
• Language: Italian; English
• Published: 2004
• Subjects: Antarctic; The Antarctic; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/11590/272390

The development of extensional basins is commonly explained as induced by the kinematics of tectonic plates (lithospheric stretching and flexure, strike-slip-related basins) and by the density imbalances produced by oceanic ridges, continental margins and plateau uplifts. Strike-slip-related basins are commonly associated to transform plate boundaries, to obliquely-converging plate boundaries where deformation is fully partitioned into dip-slip and strike-slip faulting, and to intraplate strike-slip deformation belts transferring displacement from convergent plate boundaries to the plate interiors. The occurrence of strike-slip deformation belts that are significantly active in intraplate regions is possibly uncommon in divergent plate boundaries, that are generally believed to be dominated by sea floor spreading and passive margin development. Plate tectonics theory does not predict any strike-slip movement along fracture zones once they pass outboard of their associated ridge segments and away from the plate boundary. In this contribution we illustrate the Cenozoic geodynamic framework at the northeastern edge of the Antarctic plate, where we believe there is strong evidence for the occurrence of post-rift strike-slip deformation belts including both the intraridge (transform) and out-of-ridge segments of fracture zones, and their collinear onshore strike-slip fault systems. These impressively long strike-slip belts transfer differential spreading at the constructional plate boundary into the plate interior, where residual horizontal displacement is accommodated in a lithosphere-scale horsetail array of transtensional basins. Deep basins originated also along the main traces of these intraplate strike-slip belts, both in oceanic and continental crust. Basin opening to accommodate displacement associated to intraplate strike-slip deformation belts dissecting passive margins provides an additional geodynamic scenario for explaining the occurrence of important extensional deformations in the plate interiors.